1. Technical Field of the Invention
The present invention relates to an electronic device such as a personal computer or TV video game unit having cooling unit that prevents the temperature from rising inside an electronic circuit module due to heat generated by electronic components mounted on an electronic circuit module.
2. Description of the Related Art
In recent years, as TV video games and laptop-type personal computers have become more sophisticated, the electronic components used therein have become more densely concentrated and the speed with which the integrated circuits operate has increased. As a result, the temperature increase caused by heat generated by electronic circuit modules composed of a plurality of electronic components can damage and sometimes even destroy beyond repair the integrated circuits themselves.
Generally, the heat generated by electronic components increases as power consumption and operating speed increase, so the electronic circuit module requires a cooling unit to restrain the temperature rise.
Typically, in such types of electronic circuit modules, forked radiator panels or a cooling fan are mounted on the heat-producing element in order to forcibly cool the unit.
Additionally, there are radiators for electronic devices that contact an aluminum block surface with the heat-producing element and conduct the generated heat to a fan via a heat pipe, the fan then discharging the heat externally.
For example, the radiator internal to the electronic device disclosed in Japanese Laid-Open Patent Application No. 10-126080 consists of a single piece of hollow extruded aluminum, comprising on an intake side a heat transfer portion for transferring heat received externally from within the electronic circuits to an internal flow of air, a flow duct on an exit side having a fan compartment shaped so as to accommodate an exhaust fan, and an exhaust fan contained within the fan compartment of the air flow duct, with air introduced from outside the electronic device sent through the air flow duct and discharged outside the electronic device.
Additionally, an electronic circuit module comprising a temperature sensor installed on an electronic circuit module that senses a module temperature, a first-stage temperature setting unit that outputs a signal indicating that a first-stage temperature has been exceeded when the module temperature measured by the temperature sensor exceeds a previously determined first-stage temperature, a fan unit that cools the electronic circuit module that is triggered by the output signal of the first-stage temperature setting unit, a second-stage temperature setting unit that outputs a signal indicating that a second-stage temperature has been exceeded when the module temperature measured by the temperature sensor exceeds a previously determined second-stage temperature, and a power cutoff unit that cuts off the supply of power to the electronic circuit module in response to the output signal from the second-stage temperature setting unit, is described in Japanese Laid-Open Patent Application No. 8-126191.
Moreover, a configuration in which, when a temperature detection signal from a temperature sensor detecting a temperature in the vicinity of an image processing LSI which generates a large amount of heat is output to a temperature monitoring microprocessor, a cooling fan is triggered when the temperature detected by the microprocessor is greater than a first threshold value, and a clock stop signal is output and the operation of the LSI is stopped when the temperature detected by the microprocessor is greater than a second threshold value, is disclosed in Japanese Laid-Open Patent Application No. 10-93010.
However, the conventional method of simply mounting forked radiator panels on the heat-producing element requires space for the radiator panels and is unsuitable when it comes to making electronic control devices compact.
Additionally, the method of cooling simply using a fan requires that, in order to increase the cooling effect, the size of the fan be increased or that the rpm of the fan be increased so as to increase the exhaust volume. Increasing the rotation speed of the fan also further increases the fan rotation noise. Furthermore, if for some reason the fan did not turn, the electronic circuit module could overheat.
In a cooling device that conducts heat from a heat-producing element via a heat pipe to a fan to be discharged externally, the device is a single unit from the portion that receives the heat from the heat-producing element to the portion of the fan that dissipates the heat, so if trouble occurs it is not possible to replace just the defective part. Instead, the entire unit must be replaced, leading inevitably to an increase in parts costs.
Most fundamentally, complicated cooling units with a large number of component parts complicate the work of installing and removing the units.
Moreover, as with the devices described in the publications mentioned above, the system of sensing the temperature of heat-producing elements inside the electronic module and, in response to an overheated state, using a temperature sensing microprocessor to vary or decrease the rotational speed of the cooling fan or the operating frequency of the integrated circuit and cutting the electronic module power or operating frequency, requires specialized circuits such as temperature sensors; temperature setting units and temperature monitoring microprocessors, which of course increases the cost.
The present invention was conceived with the above-described points in mind, and in order to remedy the disadvantages of electronic device cooling units, has as its object to provide a cooling unit for an electronic control device that comprises fewer parts and is thus easier to assemble, and at the same time reduces fan noise leaking to the outside by moving the fan away from the ventilation holes in the electronic device, takes a comprehensive view of thermal design by stopping the operation of the electronic circuit in the event that the fan stops rotating so as to prevent overheating, has a simple construction that moreover does not take space, is low-cost, and further, while of course preventing misoperation due to heat generated by the electronic circuit module and maintaining safety, can also cool compact, lightweight devices.
The electronic device having a cooling unit according to the present invention comprises an electronic device mounting an electronic circuit module on which electronic components are mounted and having a fan that discharges air from inside the electronic device to an outside of a component when the electronic circuit module operates, the electronic device having an exhaust port provided on a side wall of the component, a duct provided so as to contact the exhaust port on an inside of the component, and a fan portion provided on the duct inside the component, as a result of which it becomes possible to reduce the noise of the fan during rotation.
Additionally, the duct has an intake opening formed on an exterior of the casing and an exhaust opening connected to the exhaust port provided on the side wall of the component, as a result of which air discharged by the fan can be discharged externally without loss.
Additionally, the fan portion is provided on an edge of the electronic circuit board inside the component, as a result of which heat transmitted across the surface of the electronic circuit board the can be efficiently discharged externally.
Further, the fan portion hangs from the exhaust port provided in the side wall of the component, so the height of the fan portion can be lowered by designing the component accordingly.
Additionally, in an electronic device mounting an electronic circuit module on which electronic components are mounted and having a shield plate shielding the electronic circuit board so as to prevent leakage of electromagnetic waves from the electronic circuit module, a heat-receiving plate is attached to said shield plate at a mounting surface of the electronic module, a contacting portion of said heat-receiving plate contacts a high-temperature heat-producing element mounted on the electronic circuit board and another portion of the heat-receiving plate is led to a vicinity of a fan that discharges air inside the electronic device to the outside of the electronic device, as a result of which the heat produced by the high-temperature heat-producing element is received by the contacting portion of the heat-receiving plate and then dissipated to the heat-receiving plate attached to the shield plate, and at the same time the fan can efficiently discharge heat transferred to the heat-receiving plate to the outside of the electronic device.
Further, the high-temperature heat-producing element contacts a surface of the heat-receiving plate via a heat-transferring buffer, so the heat-transferring buffer maintains the surface contact between the heat-producing element and the heat-receiving plate despite slight deformations of the heat-receiving plate and it is possible to maintain superior heat-transfer capability without degradation of heat-transfer capability.
Additionally, the heat-receiving plate has an attachment surface that attaches to the shield plate and at the same time a portion of the heat-receiving plate that contacts the surface of the high-temperature heat-producing element has a heat-receiving surface of a height that varies according to a height of each of a plurality of high-temperature heat-receiving elements, each height continuous with the attachment surface via a step, so a heat-receiving plate consisting of a single member is sufficient for even a plurality of heat-producing elements, reducing the number of parts and simplifying production.
Additionally, because the heat-receiving plate comprises a cooling section adjacent to an intake port of the fan portion and heat-dispersing fins projecting from a front surface of said cooling section, the surface area exposed to the passage of the flow of air from the fan is increased and the cooling efficiency of the heat-receiving plate can be further enhanced.
Further, the shield plate on a non-mounting surface of the electronic module has a contacting portion that contacts an electronic circuit board at a rear of a high-temperature heat-producing element, said contacting portion contacting an electronic circuit board surface via the heat-transferring buffer, so heat generated by the high-temperature heat-producing element can be dissipated to the shield plate from a rear of the mounting surface and at the same time a strong structure achieved by supporting the electronic circuit board.
Additionally, the heat-receiving plate comprises an aluminum plate, as a result of which heat transfer capability is enhanced and heat can be dissipated efficiently.
Additionally, in an electronic device mounting an electronic circuit module on which electronic components are mounted and having a fan that discharges air inside the electronic device to an outside of a component when the electronic circuit module operates, the electronic device comprises a fan operating output means for detecting a rotation of a fan and operating control means for controlling an operation of the electronic circuit module based on an operating signal from said fan operating output means, as a result of which the operation of the electronic module is adjusted when the fan rotation is stopped due to the fan operating output signal, so additional heat generation can be prevented.
Additionally, the operating control means for controlling the operation of the electronic circuit module stops a clock generator that supplies a clock pulse to the electronic circuit module, as a result of which the oscillation of the clock signal is stopped by stopping the rotation of the fan, so the operation of the integrated circuits of the electronic circuit module is stopped and heat generation can be prevented.
Further, the operating control means for controlling the operation of the electronic circuit module turns power on and off, as a result of which the power is cut off when the rotation of the fan motor stops, so heat generation of the electronic circuit can be prevented.
Additionally, because the fan operating output means outputs a presence or absence of a rotation of the fan as a binary digital signal, the operating condition of the fan can be judged accurately.
Additionally, because the fan operating output means has delaying means for delaying a rotation detection signal for detecting the rotation of the fan, even if the rotation detection signal is input only intermittently the clock pulse need not be turned ON and OFF each time and thus the operation of the integrated circuit to which the clock pulse is supplied can be stabilized.
Additionally, because the fan operating output means converts to a numerical value level corresponding to the rotational state of the fan, ascertains the rotational state of the fan based on said converted numerical value, and outputs a detection signal corresponding to said fan, the rotation condition of the fan can be divided into a plurality of stages and determined accordingly, and if for some reason the fan rpm declines the clock pulse need not be stopped immediately but instead the user can be notified of the occurrence of trouble with the fan while the operation of the integrated circuit continues.
Additionally, because the operating control means changes in stages a clock pulse frequency output to the electronic circuit module in response to the detection signal output from the fan operating output means, the operation of the integrated circuits on the electronic circuit module can be decreased in stages according to the operating condition of the fan, and at the same time as trouble occurs with the fan the clock pulse can be stopped, to ease the burden on the user.
Additionally, because the fan operating output means is triggered by an image synchronization signal and detects the rotational state of the fan, there is no need to provide a special signal generating means in order to monitor the rotation condition of the fan and thus the structure can be simplified and costs can be held down.
Other objects, features and advantages of the present invention will become apparent from the following detailed description when read in conjunction with the accompanying drawings.